1. Field of the Invention
The invention relates to a zoom optical system having a compact structure and realizing high magnification.
2. Description of the Related Art
Currently, optical imaging devices such as digital cameras or video cameras having an imaging device, such as a charge coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS), are widely spread. Optical imaging devices are required to have high performance, such as high magnification and high pixel number. In addition, optical imaging devices are required to be small, light and inexpensive. Thus, the imaging optical devices are required to have high performance such as increased magnification and pixel number and to be small, light and inexpensive. Accordingly, a zoom optical system including an optical imaging device is also required to have high performance and to be inexpensive.
In order to realize a high-pixel large-sized imaging device, the number of lenses included in a zoom optical system has gradually increased, and a lens full length has increased. In order to simultaneously achieve a compact and high-definition zoom optical system, a glass lens, particularly, a glass aspherical lens, may be used. In this case, the weight and manufacturing costs of the zoom optical system increase since high precision and high processing costs are required to process the glass aspherical lens.